The within invention is directed a method and an electromagnetic antenna extension assembly, including at least one extension tool, for extending a downhole electromagnetic antenna providing or transmitting data, such as measurement-while-drilling telemetry data, to the surface. More particularly, the electromagnetic antenna is extended by extending the length of a lower electrode of the electromagnetic antenna such that the electromagnetic signal transmitted by the antenna is propagated or launched into the surrounding casing and/or the formation closer to the surface. Preferably, the method and the assembly provide for the extension of the antenna, and particularly the lower electrode, by providing for the connection of one or more extension tools into a pipe string, such as a drill string, downhole of the antenna.
For many parts of the world there are hydrocarbon producing zones that need to be drilled underbalanced or near balance making use of aerated drilling mud, or 2 phase or air drilling applications. In these instances, electromagnetic (xe2x80x9cEMxe2x80x9d) data transmitters or transmission units, such as EM measurement-while-drilling (xe2x80x9cMWDxe2x80x9d) systems, are used as they do not rely on pressure pulses through a continuous mud or fluid column to transmit telemetry data to the surface. Rather, the telemetry data is transmitted to the surface using a downhole transmitter antenna which produces EM waves into the formation that are picked up by a receiving antenna array located at the ground surface or sea floor and the wellhead. Specifically, EM MWD systems create an alternating current circuit with the drill string as one conductor and the earth or surrounding formation as the other conductor.
More particularly, in these systems, telemetry data is input from a downhole data transmission unit, including a data transmission tool such as an EM MWD tool, located adjacent or in proximity to the drilling bit or other bottom hole equipment, to an electromagnetic antenna such as an EM MWD antenna positioned downhole in the drill string. The EM antenna transmits the electromagnetic signal, which is detected at the surface.
The downhole data transmission tool or EM MWD tool, which senses and provides the telemetry data or information signals, is typically housed or contained within an outer transmission sub or member, such as an index or hang off sub. The EM MWD tool is held or supported within the index sub, such as by a hang off ring mounted or connected with the index sub. The hang off ring also acts as a lower electrode contact ring. A lower or downhole end of the index sub is connected with the drill bit or other equipment comprising the bottom hole assembly. An upper or uphole end of the index sub is typically connected with the EM antenna.
The EM MWD antenna is typically comprised of an outer antenna sub or member having an upper portion and a lower portion separated by an electrically insulative gap. Further, the EM antenna is typically comprised of an electrically conductive inner antenna member, being a wireline or cable, hung off the EM antenna and extending downhole for connection with the EM MWD tool. More particularly, an upper end of the EM antenna wireline connects with the upper portion of the EM outer antenna sub or member above the insulative gap. A lower end of the EM antenna wireline is comprised of a connector, preferably comprised of a collet overshot, for connection with the EM MWD tool. Specifically, the upper end of the EM MWD tool provides a connector compatible with the EM antenna wireline connector, preferably a contact stinger or probe. The EM antenna wireline is preferably insulated so if it contacts the inside of the outer antenna sub or member or any other portion of the pipe or drill string it will not short out the electromagnetic signal.
As a result of the above configuration of the EM antenna and the EM MWD tool, the upper portion of the outer antenna sub or member and the uphole part or portion of the drill string to the surface provide the upper electrode of the EM antenna. Further, the lower portion of the outer antenna sub or member and the downhole part or portion of the drill string to the drill bit provide the lower electrode of the EM antenna.
However, the propagation of EM waves by the EM antenna is characterized by an increase in attenuation with an increase in distance or an increase in the depth of the EM antenna. Thus, for many of the above-described zones it is difficult or impossible to drill with a conventional EM MWD system as the range required is too far for the telemetry to work in a satisfactory manner. The primary problem is the depth at which the intermediate casing must be set at prior to entering the underbalanced zone. Since the transmitted EM signal tends to be relatively greatly attenuated by approximately 20 dB in relative signal strength when the EM antenna is inside the casing, the maximum depth of the EM antenna tends to be limited to much shallower depths than it would be if positioned within an uncased borehole. The depths of some of these zones cause the EM signal to be greatly attenuated by the time it reaches the surface and thus the signal can not typically be detected by the surface receiver system.
To address the effects of attenuation, a repeater may be used to relay the EM signal uphole. However, where a repeater is used, the repeater tends to be relatively ineffective or less effective until it exits the intermediate casing as a result of the signal loss, being in the magnitude of about a 20 dB signal loss as discussed above. If the repeater can be located close to the surface it can be detected by the surface receiver system but the repeater may not be able to receive the signal from the lower repeaters or the main bottom hole transmitter as it is typically too far away. Adding repeaters solves the problem by having many repeaters at short distances but this solution affects the reliability of the system, adds a large capital and operating cost, and results in a decrease in the signal data rate. For instance, the data rate has been found to be halved for every repeater added, i.e. 3 repeaters would mean the signal data rate can be no faster than 1/8th of the fundamental data rate. All these options are unattractive.
A relatively more attractive option or alternative approach is to add an extension to the EM antenna which allows the first or lowermost EM antenna to be positioned much further up the drill string before launching the signal into the casing and/or the formation. More particularly, a further or additional section or length of drillpipe, referred to herein as the xe2x80x9clengthening sectionxe2x80x9d, may be connected into the drill string in-between the lower portion of the outer antenna sub or member and the outer transmission member or index sub housing the EM MWD tool. In other words, the lower portion of the outer antenna sub or member is comprised of the lengthening section. Thus, the lengthening section of drillpipe forms a part of the lower electrode of the EM antenna. The resulting lengthened lower electrode moves or positions the launching point of the EM signal much further uphole. In this instance, the length of the conductive inner antenna member, being the EM antenna wireline, is also increased so that the EM antenna wireline, being a single section or length of wireline or cable, can extend substantially from the upper portion of the outer antenna sub or member, through the lower portion of the outer antenna sub or member including the lengthening section, for connection with the EM MWD tool.
This approach has various advantages and disadvantages. The key advantage is that the lower electrode of the EM antenna may be greatly lengthened or extended by this lengthening section of drillpipe which allows for a stronger signal to be generated. Also the EM antenna is moved closer to the surface making detection of the electromagnetic signal at the surface relatively easier. Typically these lengthening sections can be from 100 feet to thousands of feet or more.
The key limitation with respect to extending the EM antenna by the use of a lengthening section is the length of the EM antenna wireline required to be used. Specifically, the maximum length of the wireline of the EM antenna is limited by the angle or inclination of the borehole being drilled. For instance, the angle of the borehole typically builds with depth, which tends to interfere with the ability of the collet overshot at the lower end of the EM antenna wireline to correctly connect with the contact stinger of the EM MWD tool. Thus, the length of the lengthening section that may be added to the outer antenna sub or member of the EM antenna will be limited by the distance that can be traversed with a single section of wireline or cable, which is dependent upon the borehole. In some instances this limitation prevents a length of drillpipe from being installed that is long enough to appropriately or satisfactorily extend the EM antenna to meet the needs of the telemetry.
Thus, there remains a need in the industry for an improved method and a downhole assembly or tool for extending a downhole EM antenna, and specifically for extending a lower electrode of the EM antenna, thus permitting the placement of the EM antenna closer to the surface. Further, there remains a need in the industry for an EM antenna extension assembly for connection into a drill string between a downhole EM data transmission unit, such as an EM MWD system, and a downhole EM transmitter antenna. As well, there is a need for a method for connecting the downhole data transmission unit with the downhole EM antenna such that the EM antenna is extended thereby.
The within invention is directed at a method and an assembly or a tool which take the upper electrode of the EM antenna and move it to a point or location downhole nearer the surface through the use of an extension assembly comprised of at least one extension tool including an electrically conductive inner member, such as a wireline, cable or any other suitable electrical conductor that is positioned inside an electrically conductive outer member, such as a pipe, including a drill pipe, or a coil tubing string.
Further, the within invention is directed a method and an assembly or tool for extending a downhole EM antenna providing downhole data, such as EM MWD telemetry data, or EM signals to the surface. Preferably, the EM antenna is extended by moving the EM antenna closer to the surface within the borehole. More preferably, the extension method, the EM antenna extension assembly or one or more extension tools provide for the lengthening of the lower electrode of the EM antenna such that the EM signal is launched or transmitted into the casing and/or the formation by the EM antenna further uphole or closer to the surface. In the preferred embodiment, the extension method and extension assembly lengthen the lower electrode of the EM antenna by connecting one or more extension tools into a pipe string, such as a drill string, between the EM antenna and the EM MWD tool.
In a first aspect of the invention, the invention is comprised of an electromagnetic antenna extension assembly for connection into a pipe string between a downhole data transmission unit for generating an electromagnetic signal and a downhole electromagnetic antenna for transmitting the electromagnetic signal, wherein the downhole electromagnetic antenna is of a type comprising a conductive outer antenna member and a conductive inner antenna member therein having a lower electrical connector and wherein the downhole data transmission unit is of a type comprising a conductive outer transmission member and an inner data transmission tool therein having an upper electrical connector connectable with the lower connector of the inner antenna member, the electromagnetic antenna extension assembly comprising at least one extension tool comprised of:
(a) an electrically conductive outer extension member having an upper end connectable with the outer antenna member and a lower end connectable with the outer transmission member; and
(b) an electrically conductive inner extension member mounted and extending within the outer extension member and having an upper end connectable with the lower connector of the inner antenna member and a lower end connectable with the upper connector of the inner data transmission tool;
such that the electromagnetic signal is communicable between the downhole data transmission unit and the downhole electromagnetic antenna.
More particularly, each extension tool is comprised of a tubular electrically conductive outer member or sleeve and an electrically conductive inner member which is preferably electrically insulated from the outer member. Specifically, the outer extension member is electrically insulated from the inner extension member. More particularly, the outer extension member has an inner surface and the inner extension member has an outer surface. The inner surface may be a spaced distance from the outer surface to provide an electrically insulative gap therebetween. Preferably, the extension tool is further comprised of an insulator between the inner surface of the outer extension member and the outer surface of the inner extension member for electrically insulating the outer extension member from the inner extension member.
Any type of electrical insulator or electrically insulative material may be used which is capable of electrically insulating the inner extension member from the outer extension member. Further, the insulator may be positioned within the gap provided by the spaced distance between the adjacent inner and outer surfaces of the outer and inner extension members respectively. As well, the insulator may be associated, mounted or connected with one or both of the inner and outer surfaces. Preferably, the insulator is comprised of an insulative coating associated with at least one of the outer surface of the inner extension member and the inner surface of the outer extension member. Thus, the inner surface of the outer extension member may be comprised of the insulative coating. However, in the preferred embodiment, the outer surface of the inner extension member is comprised of the insulative coating.
As stated, the electrically conductive outer extension member has an upper end connectable with the outer antenna member and a lower end connectable with the outer transmission member such that the electromagnetic signal is communicable between the outer antenna member and the outer transmission member. Thus, the upper end of the outer extension member is adapted or configured to be compatible for attachment or connection, either permanently or detachably, in series with the outer antenna member. Although any compatible configuration may be used, the outer antenna member is preferably comprised of a threaded pin or male connector, while the upper end of the outer extension member is comprised of a compatible threaded box or female connector for receipt of the male connector therein.
Similarly, the lower end of the outer extension member is adapted or configured to be compatible for attachment or connection, either permanently or detachably, in series with the outer transmission member. Although any compatible configuration may be used, the outer transmission member is preferably comprised of a threaded box or female connector, while the lower end of the outer extension member is comprised of a compatible threaded pin or male connector for receipt within the female connector.
The outer extension member may be comprised a single, unitary tubular portion, sub or sleeve extending between its upper and lower ends. Alternately, the outer extension member may be comprised of two or more tubular sections, portions, subs or sleeves interconnected to provide the outer extension member having the upper and lower ends. Where two or more sections are interconnected, the sections may be connected, affixed, mounted or otherwise joined together in series, permanently or detachably, in any manner and by any suitable mechanism for connecting the adjacent ends of each such section such that the outer extension member formed thereby is electrically conductive between its upper and lower ends. Preferably, a detachable connection, such as a threaded box and pin connection, is provided between adjacent sections comprising the outer extension member.
In the preferred embodiment, the conductive outer extension member is comprised of a top section, which may also be referred to as an extender sub, defining the upper end of the outer extension member connected with a bottom section defining the lower end of the outer extension member. Each of the top and bottom sections may be comprised of one or more tubular portions, subs or sleeves interconnected to provide the respective section. However, preferably, the top section is comprised of a single, unitary tubular portion, sub or sleeve connected with the bottom section. The bottom section may connected, mounted, affixed or otherwise joined with the top section in any manner and by any structure, mechanism or device, but is preferably connected by a threaded connection therebetween. Further, the bottom section is preferably comprised of two or more tubular portions, subs or sleeves connected together in series. Preferably, the overall length of the extension tool, and particularly the conductive outer extension member, is varied by varying the length of the bottom section.
Preferably, the outer extension member is comprised of at least one length, joint or section of pipe, for example a drill pipe, or at least one length or section of coiled tubing. Further, in the preferred embodiment, each of the top section and the bottom section is comprised of at least one length of pipe or at least one length of coiled tubing.
As indicated, the extension tool is connected into the pipe string between the subdownhole data transmission unit and the downhole electromagnetic antenna. Thus, the outer extension member is connected between the outer antenna member and the outer transmission member. As discussed above, a further or additional section or length of pipe, referred to as a lengthening section may be connected with the lowermost end or lower portion of the outer antenna member. Accordingly, the outer antenna member, and particularly its lower portion, is comprised of the lengthening section. In this case, the upper end of the outer extension member is particularly connectable with the lengthening section. In any event, the extension tool is connected into the pipe string such that the conductive outer extension member forms a part of the lower electrode of the EM antenna.
The outer extension member of the extension tool, and thus the extension tool itself, may be of any length, subject to the limitations set out below. However, in the event that the length of any particular extension tool is limited, two or more extension tools may be used to extend the EM antenna by lengthening the lower electrode. Specifically, two or more of the extension tools may be combined and connected into the pipe string between the EM antenna and the data transmission unit to provide the desired distance or length therebetween.
Further, each extension tool is comprised of the electrically conductive inner extension member which extends within the electrically conductive outer extension member and is mounted, connected or otherwise affixed within the inner surface of the outer extension member while preferably electrically insulating the signal path of the inner extension member from the outer extension member. The conductive inner extension member may be mounted, connected or affixed within the outer extension member or held in position within the outer extension member by any mechanism, device, structure or method capable of and suitable for maintaining the position of the inner extension member therein. In the preferred embodiment, the inner extension member is mounted, connected or held within the outer extension member, preferably within the top section thereof. More particularly, the upper end of the inner extension member is mounted within the top section of the outer extension member.
The conductive inner extension member has an upper end and a lower end. The upper end of the conductive inner extension member is adapted or configured to be compatible for connection with the conductive inner member of the EM antenna, particularly the lower connector of the inner antenna member. Similarly, the lower end of the conductive inner extension member is adapted or configured to be compatible for connection with the inner data transmission tool, particularly the upper connector thereof.
The upper end of the inner extension member is preferably comprised of an upper electrical connector or fastener compatible with the lower connector of the inner antenna member of the EM antenna for connection therewith. Similarly, the lower end of the inner extension member is preferably comprised of a lower electrical connector or fastener compatible with the upper connector of the inner data transmission tool for connection therewith.
Although any compatible electrical upper and lower connectors may be used, preferably, each of the lower connector of the inner antenna member and the lower connector of the inner extension member is comprised of a female connector and each of the upper connector of the inner extension member and the upper connector of the inner data transmission tool is comprised of a compatible male connector for insertion in the female connector. Further, although any compatible malexe2x80x94female connectors may be used, each female connector is preferably comprised of a collet overshot while each male connector is preferably comprised of a contact stinger or probe for insertion within the collet overshot. Thus, in the preferred embodiment, each of the lower connector of the inner antenna member and the lower connector of the inner extension member is comprised of a collet overshot, while each of the upper connector of the inner extension member and the upper connector of the inner data transmission tool is comprised of a compatible contact stinger or probe.
In addition, the extension tool may be further comprised of at least one centralizer associated with the inner extension member for centralizing the inner extension member within the outer extension member. In the preferred embodiment, at least one centralizer is associated with the lower end of the inner extension member.
The conductive inner extension member is preferably comprised of a unitary member or single piece or length extending between its upper and lower ends, although two or more members, pieces or lengths may be connected, attached or affixed together where necessary to provide the conductive inner extension member. Further, the conductive inner extension member may be comprised of any conductive material. For instance, the inner extension member may be comprised of a wireline, a length of coiled tubing or at least one length, portion or joint, and preferably multiple joints, of pipe or tubing such as production tubing. In this case, the tubing such as the production tubing is preferably at least partially electrically insulated from the outer extension member.
However, the inner extension member is preferably comprised of a wireline or cable. In this case, the wireline or cable is preferably insulated from the inner surface of the conductive outer extension member. Thus, an insulated wire or cable, or a wireline having an insulative coating or an insulating jacket on the outer surface thereof, may be used. Alternately, the inner surface of the outer extension member may be coated with an insulator or provided with an insulative coating and a bare or uninsulated wireline or cable used therein.
Alternatively, the conductive inner extension member may be comprised of a length of coil tubing. In this case, the coil tubing is also preferably insulated from the inner surface of the outer extension member. Thus, an insulated coil tubing, or a length of coiled tubing having an insulative coating, may be used or alternately, the inner surface of the outer extension member may be provided with an insulative coating and a bare or uninsulated length of coil tubing used therein.
Further, in the preferred embodiment, the extension tool may be likened to a coaxial cable in which the outer conductor is the pipe or coil tubing and the inner conductor is a preferably insulated conductive wireline cable.
The length of the conductive inner extension member may be limited by the inclination of the borehole, which will in turn limit the overall length of the extension tool. However, as discussed below, two or more extension tools may be combined or connected together to provide the desired extension length. Thus, although the length of each individual extension tool may be limited, the overall length of the desired extension of the EM antenna and the desired length of the lower electrode of the EM antenna, may still be achieved.
As stated, the electromagnetic antenna extension assembly may be comprised of at least two extension tools connected in series. As discussed below with respect to the method of the within invention, in this case, the EM antenna extension assembly is comprised of a first extension tool and at least one second extension tool. In the preferred embodiment, the first extension tool and each second extension tool are substantially similar with respect to the structure and configuration of the elements comprising the tool. Each extension tool may however differ with respect to the overall length of the tool. Thus, each of the first extension tool and the second extension tool are as described above for the preferred embodiment of the invention in its first aspect.
Where the electromagnetic antenna extension assembly is comprised of at least two extension tools connected in series, the lower end of the outer extension member is further connectable with the upper end of an adjacent outer extension member and the lower end of the inner extension member is further connectable with the upper end of an adjacent inner extension member such that the electromagnetic signal is communicable between the downhole data transmission unit and the downhole electromagnetic antenna.
In other words, in order that one or more extension tools may be used as desired or required for any particular application, including any drilling application, the upper end of the outer extension member of each extension tool is preferably connectable with both the outer antenna member and the lower end of an adjacent outer extension member, as necessary, and the lower end of the outer extension member of each extension tool is preferably connectable with both the outer transmission unit and the upper end of an adjacent outer extension member, as necessary. Thus, each outer extension member may be connected into the antenna extension assembly at any position or location along the length of the assembly.
In the preferred embodiment, this connectability is provided by a threaded connection between each adjacent end. More particularly, each of the outer antenna member and the lower end of the outer extension member is comprised of a threaded pin or male connector, while each of the outer transmission member and the upper end of the outer extension member is comprised of a compatible threaded box or female connector for receipt of the male connector therein.
Similarly, in order that one or more extension tools may be used as desired or required for any application, including any drilling application, the upper end of the inner extension member of each extension tool is also preferably connectable with both the lower connector of the inner antenna member and the lower end of an adjacent inner extension member, as necessary, and the lower end of the inner extension member of each extension tool is preferably connectable with both the upper connector of the inner data transmission tool and the upper end of an adjacent inner extension member, as necessary. Thus, each inner extension member may be connected into the antenna extension assembly at any position or location along the length of the assembly.
In the preferred embodiment, as discussed above, this connectability is provided by an electrical connector at each adjacent end. The upper end of the inner extension member is comprised of the upper electrical connector and the lower end of the inner extension member is comprised of the lower electrical connector, both as previously described. The upper electrical connector of the inner extension member is compatible for connection with both the lower connector of the inner antenna member and the lower connector of an adjacent inner extension member, as necessary, while the lower electrical connector of the inner extension member is compatible for connection with both the upper connector of the inner data transmission tool and the upper connector of an adjacent inner extension member, as necessary.
More particularly, in the preferred embodiment, each of the lower connector of the inner antenna member and the lower connector of the inner extension member is comprised of a female connector, preferably a collet overshot. Further, each of the upper connector of the inner extension member and the upper connector of the inner data transmission tool is comprised of a compatible male connector, preferably a contact stinger or probe, for insertion in the female connector.
In a second aspect of the invention, the invention is comprised of a method for connecting a downhole data transmission unit for generating an electromagnetic signal with a downhole electromagnetic antenna for transmitting the electromagnetic signal, wherein the downhole electromagnetic antenna is of a type comprising a conductive outer antenna member and a conductive inner antenna member therein having a lower electrical connector and wherein the downhole data transmission unit is of a type comprising a conductive outer transmission member and an inner data transmission tool therein having an upper electrical connector connectable with the lower connector of the inner antenna member, the method comprising the steps of:
(a) providing an electromagnetic antenna extension assembly comprising at least one extension tool, wherein the extension tool is comprised of an electrically conductive outer extension member having an upper end and a lower end and an electrically conductive inner extension member having an upper electrical connector and a lower electrical connector;
(b) connecting the lower end of the outer extension member with the outer transmission member;
(c) inserting the inner extension member within the outer extension member such that the lower connector of the inner extension member is connected with the upper connector of the inner data transmission tool;
(d) connecting the outer antenna member with the upper end of the outer extension member;
(e) inserting the inner antenna member within the outer antenna member such that the lower connector of the inner antenna member is connected with the upper connector of the inner extension member.
Although the method described herein may be performed using any compatible electromagnetic antenna extension assembly, the within method is preferably performed utilizing the EM antenna extension assembly, and preferably the preferred embodiment thereof, as described herein.
Thus, as described above, the outer extension member is comprised of a top section and a bottom section and the upper connector of the inner extension member is mounted within the top section. In this instance, step (b) of the method is comprised of connecting the bottom section defining the lower end with the outer transmission member and step (c) of the method is comprised of inserting the inner extension member within the bottom section of the outer extension member such that the lower connector of the inner extension member is connected with the upper connector of the inner data transmission tool and connecting the top section with the bottom section of the outer extension member. Further, where the bottom section of the outer extension member is comprised of greater than one length of pipe or coiled tubing, step (b) of the method is preferably further comprised of connecting each length of pipe or coiled tubing in series to provide the bottom section.
In a third aspect of the invention, the invention is comprised of a method for connecting a downhole data transmission unit for generating an electromagnetic signal with a downhole electromagnetic antenna for transmitting the electromagnetic signal, wherein the downhole electromagnetic antenna is of a type comprising a conductive outer antenna member and a conductive inner antenna member therein having a lower electrical connector and wherein the downhole data transmission unit is of a type comprising a conductive outer transmission member and an inner data transmission tool therein having an upper electrical connector connectable with the lower connector of the inner antenna member, the method comprising the steps of:
(a) providing an electromagnetic antenna extension assembly comprising a first extension tool and at least one second extension tool, wherein each extension tool is comprised of an electrically conductive outer extension member having an upper end and a lower end and an electrically conductive inner extension member having an upper electrical connector and a lower electrical connector;
(b) connecting the lower end of the outer extension member of the first extension tool with the outer transmission member;
(c) inserting the inner extension member of the first extension tool within the outer extension member of the first extension tool such that the lower connector of the inner extension member of the first extension tool is connected with the upper connector of the inner data transmission tool;
(d) connecting the lower end of the outer extension member of the second extension tool with the upper end of the outer extension member of the first extension tool;
(e) inserting the inner extension member of the second extension tool within the outer extension member of the second extension tool such that the lower connector of the inner extension member of the second extension tool is connected with the upper connector of the inner extension member of the first extension tool;
(f) connecting the outer antenna member with the upper end of the outer extension member of the second extension tool; and
(g) inserting the inner antenna member within the outer antenna member such that the lower connector of the inner antenna member is connected with the upper connector of the inner extension member of the second extension tool.
Further, the method preferably comprises the steps prior to step (f) of:
(h) connecting the lower end of the outer extension member of at least one further second extension tool with the upper end of the outer extension member of the prior second extension tool;
(i) inserting the inner extension member of the further second extension tool within the outer extension member of the further second extension tool such that the lower connector of the inner extension member of the further second extension tool is connected with the upper connector of the inner extension member of the prior second extension tool;
wherein steps (f) and (g) connect the electromagnetic antenna with the uppermost further second extension tool.
Again, the within method is preferably performed utilizing the EM antenna extension assembly, and preferably the preferred embodiment thereof, as described herein. Specifically, the outer extension member of each extension tool is preferably comprised of a top section and a bottom section and the upper connector of the inner extension member is mounted within the top section. In this instance, in the third aspect of the invention, step (b) of the method is comprised of connecting the bottom section defining the lower end of the outer extension member of the first extension tool with the outer transmission member and step (c) of the method is comprised of inserting the inner extension member of the first extension tool within the bottom section of the outer extension member of the first extension tool such that the lower connector of the inner extension member is connected with the upper connector of the inner data transmission tool and connecting the top section with the bottom section of the outer extension member of the first extension tool.
Where the bottom section of the outer extension member of the first extension tool is comprised of greater than one length of pipe or coiled tubing, step (b) of the method is further comprised of connecting each length of pipe or coiled tubing in series to provide the bottom section.
Further, step (d) of the method is preferably comprised of connecting the bottom section defining the lower end of the outer extension member of the second extension tool with the upper end of the outer extension member of the first extension tool and step (e) of the method is preferably comprised of inserting the inner extension member of the second extension tool within the bottom section of the outer extension member of the second extension tool such that the lower connector of the inner extension member of the second tool is connected with the upper connector of the inner extension member of the first extension tool and connecting the top section with the bottom section of the outer extension member of the second extension tool.
Where the bottom section of the outer extension member of the second extension tool is comprised of greater than one length of pipe or coiled tubing, step (d) of the method is further comprised of connecting each length of pipe or coiled tubing in series to provide the bottom section.